Thread Feeding Apparatus for an Automatic Embroidering Machine

ABSTRACT

The present invention relates to a thread feeding apparatus for an automatic embroidering machine supplying an upper thread from a thread supplying unit to a needle, comprising a thread tension adjuster having a thread contact portion allowing an upper thread to be at least partially wound thereon and be in contact therewith, and resisting the upper thread passing through the thread contact portion to adjust the tension of the upper thread; a take-out unit provided to rotate about a predetermined rotation axis, and rotated while holding the upper thread spaced from the rotation axis to put the upper thread on the thread tension adjuster; and a take   out driver driving the thread take-out unit to rotate for at least partially winding the upper thread on the thread contact portion. Thus, the present invention provides a thread feeding apparatus for an automatic embroidering machine, which conveniently adjusts the tension of an upper thread and reduces work time.

FIELD OF THE INVENTION

The present invention relates to a thread feeding apparatus for anautomatic embroidering machine, and more particularly, to a threadfeeding apparatus for an automatic embroidering machine, having animproved structure of adjusting the tension of an upper thread.

BACKGROUND ART

An automatic embroidering machine is a kind of a sewing machine, whichuses various colored threads and automatically embroiders apredetermined pattern, a trademark, or the like on clothes, a label ofshoes, etc. according to a preset program.

In general, the automatic embroidering machine includes a head stemprovided in front of a stationary frame; an upper thread supplying unitmounted to the head stem and supplying various colored upper threadsfrom a plurality of bobbins toward an embroidering work place; and aneedle-working unit sewing the supplied upper threads and performingembroidering works.

Further, the automatic embroidering machine is classified into a singleneedle type and a multi needle type according to the number of needlesmounted in the upper thread supplying unit and the needle-working unit.

The single needle type automatic embroidering machine includes the upperthread supplying unit to supply one selected among various colored upperthreads from the plurality of bobbins to the needle-working unit, andthe needle-working unit having a single needle to sew one supplied upperthread and perform the embroidering works.

The multi needle type automatic embroidering machine includes the upperthread supplying unit to supply various colored upper threads from theplurality of bobbins to the needle-working unit, and the needle-workingunit having a plurality of needles to sew the respective supplied upperthreads and perform the embroidering works by one selected among theneedles.

Hereinafter, the single needle type automatic embroidering machine willbe described.

The conventional signal needle type automatic embroidering machine hasbeen disclosed in Korean Patent Publication No. 2002-0068028, titled of“Thread feeding apparatus for automatic embroidering machine.”

Such a conventional thread feeding apparatus for the automaticembroidering machine includes a head stem having the needle-workingunit; the thread supplying unit to supply one selected among variouscolored upper threads; a guide pipe assembly including a first guidepipe provided in the head stem and receiving the thread from the threadsupplying unit, and a second guide pipe having an upper end spaced fromthe first guide pipe, forming a predetermined spaced portion along anaxis direction and a lower end adjacent to the needle-working unit; anda thread take-up unit including an oscillating lever oscillating on aplane parallel with a thread supplying path, and a thread retainercoupled to a free end of the oscillating lever transversely to anoscillating direction of the oscillating lever andstrengthening/releasing the tension of the thread by reciprocatingwithin the spaced portion as the oscillating lever oscillates. Thus, thehead stem is simplified, and excludes a curved path from a threadtransferring path, thereby smoothly supplying the thread.

Further, the conventional thread feeding apparatus for the automaticembroidering machine includes a thread tension maintainer provided in anupper side of the head stem and adjusting the tension of the upperthreads extended from the plurality of bobbins.

However, the conventional thread feeding apparatus for the automaticembroidering machine adjusts the tension of all upper threads extendedfrom the plurality of bobbins, so that its structure is complicated, anda user has to connect the upper threads to the thread tension maintainerone by one and adjust the tension of the upper threads. Therefore, it isnot easy to adjust the tension of the upper threads and it takes muchwork time.

DISCLOSURE OF INVENTION

Accordingly, it is an aspect of the present invention to provide athread feeding apparatus for an automatic embroidering machine, whichconveniently adjusts the tension of an upper thread and reduces worktime.

The foregoing and other aspects of the present invention are achieved byproviding a thread feeding apparatus for an automatic embroideringmachine supplying an upper thread from a thread supplying unit to aneedle, comprising a thread tension adjuster having a thread contactportion allowing an upper thread to be at least partially wound thereonand be in contact therewith, and resisting the upper thread passingthrough the thread contact portion to adjust the tension of the upperthread; a take-out unit provided to rotate about a predeterminedrotation axis, and rotated while holding the upper thread spaced fromthe rotation axis to put the upper thread on the thread tensionadjuster; and a take-out driver driving the thread take-out unit torotate for at least partially winding the upper thread on the threadcontact portion.

According to an aspect of the present invention, the take-out drivercomprises a rotation shaft coupled to the take-out unit and rotating; adriving shaft spaced from the rotation shaft at a predetermined axisdistance; a shaft driver driving the driving shaft to rotate; and apower transmission unit provided between the rotation shaft and thedriving shaft and transmitting a rotational force from the driving shaftto the rotation shaft.

According to an aspect of the present invention, the thread feedingapparatus further comprises an oscillating bracket including a threadretainer to retain the upper thread transferred from the thread tensionadjuster to the needle, and oscillating to strengthen and release thetension of the upper thread; a bracket driver driving the oscillatingbracket to move the thread retainer of the oscillating bracket on athread transferring path and put the upper thread on the threadretainer; and an oscillating bracket elastic member elastically urgingthe oscillating bracket to oscillate.

According to an aspect of the present invention, the thread feedingapparatus according to claim 1, wherein the bracket driver comprises abracket driving cam formed with a cam profile on a lateral surfacethereof; a moving pin moving along the camp profile of the bracketdriving cam; and a cam driver to rotate the bracket driving cam bymoving the moving pin along the cam profile of the bracket driving cam,wherein the oscillating bracket elastic member has a first end supportedby the bracket driving cam and a second end supported by the oscillatingbracket, and oscillates the oscillating bracket.

According to an aspect of the present invention, the bracket driverfurther comprises a cam elastic member elastically rotating the bracketdriving cam to return an original position.

According to an aspect of the present invention, the thread feedingapparatus further comprises a thread take-up unit oscillating within apredetermined section to strengthen and release the tension of the upperthread; and a thread-take-out unit taking out the upper threadtransferred from the thread tension adjuster to the needle workingportion, and putting the upper thread on the thread take-up unit and thethread retainer, wherein the oscillating bracket oscillates in avertical direction corresponding to the thread take-up unit.

According to an aspect of the present invention, the thread retainer isplaced at a top dead point of the oscillating bracket when the threadtake-up unit is placed at a top dead point thereof, and placed at abottom dead point of the oscillating bracket when the thread take-upunit is placed at a bottom dead point thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a thread feeding apparatus foran automatic embroidering machine according to a first embodiment of thepresent invention.

FIG. 2 is a partial sectional view of the thread feeding apparatus forthe automatic embroidering machine of FIG. 1.

FIG. 3 is a partially enlarged perspective view of FIG. 2.

FIG. 4 is an exploded perspective view of FIG. 3.

FIGS. 5A, 5B, 6A and 6B are partial enlarged perspective views and sidesectional views of illustrating processes of winding an upper thread ona thread tension adjuster of FIG. 2.

FIGS. 7A and 7B are plan views illustrating processes of winding theupper thread on a taking out unit and an oscillating bracket.

FIGS. 8A, 8B, 9A, 9B, 10A and 10B are side plan views illustratingprocesses of operating a bracket driver.

FIG. 11 is a partially enlarged perspective view of a thread feedingapparatus for an automatic embroidering machine according to a secondembodiment of the present invention.

FIG. 12 is an exploded perspective view of FIG. 11.

FIGS. 13A and 13B are partially enlarged perspective views illustratingprocesses of operating a thread take-up unit and an oscillating bracketof FIG. 11.

FIGS. 14A and 14B are sectional views illustrating processes ofoperating the thread take-up unit and the oscillating bracket of FIG.11.

MODES FOR CARRYING OUT THE INVENTION

Hereinbelow, a single needle automatic embroidering machine will bedescribed as an embodiment of the present invention with reference toaccompanying drawings, wherein like reference numerals refer to likeelements throughout, and repetitive descriptions will be avoided asnecessary.

As shown in FIGS. 1 through 4, a thread feeding apparatus 1 for anautomatic embroidering machine according to a first embodiment of thepresent invention includes a thread supplying unit 5 to supply one upperthread 3 selected among a plurality of upper threads different in color;a thread guide 8 to guide the upper thread 3 supplied from the threadsupplying unit 5 to a needle 13; and a thread take-up unit 11oscillating within a predetermined section, taking up the upper thread 3passing through the thread guide 8, and strengthening and releasing thetension of the upper thread 3.

The thread supplying unit 5 includes a thread supplying channel 6, andsupplies one upper thread 3 selected among the plurality of standbyupper threads different in color to the thread guide 8 using compressedair.

The thread guide 8 is formed with a thread guide channel 9 to guide theupper thread 3 supplied from the thread supplying unit 5. In thisembodiment, the thread guide 8 is shaped like a block having arectangular section, but not limited to and may be formed as a tube-likebody having various shaped sections

Meanwhile, thread supplying unit 5 and the thread guide 8 are spacedfrom each other along a thread transferring path, thereby forming aspace portion 15.

The space portion 15 includes a thread tension adjuster 21 on which theupper thread 3 passing through the space portion 15 is wound andcontacts, and adjusting the tension of the upper thread 3; and atake-out unit 25 rotating while holding the upper thread passing throughthe space portion 15, and winding the upper thread 3 on the threadtension adjuster 21.

The thread tension adjuster 21 is shaped like a disc, and has a threadcontact portion 23 recessed along the circumference thereof and on whichthe upper thread 3 is partially wound and contacts. The thread tensionadjuster 21 is accommodated in an accommodating groove 29 of thetake-out unit 25 to be described later. The thread contact portion 23resists passing the upper thread 3 being in contact therewith, therebyadjusting the tension of the upper thread 3. Preferably, the threadtension adjuster 21 is pivotally coupled to a rotation shaft 31 of atake-out driver 30 (to be described later), but not limited to.Alternatively, the thread tension adjuster 21 may be coupled to therotation shaft 31 and rotated integrally with the rotation shaft 31.

The take-out unit 25 is provided between the thread tension adjuster 21and the bottom of the thread supplying unit 5. Further, the take-outunit 25 is coupled to the rotation shaft 31 of the take-out driver 30.Here, an axis line of the rotation shaft 31 is spaced from the threadtransferring path of the upper thread 3 passing through the spaceportion 15 at a predetermined distance. Further, the take-out unit 25 isformed with a thread passing hole employed as a holder 27 holding theupper thread 3 passing the space portion 15 and passing therethrough.Alternatively, one end of the take-out unit 25 may be formed with asemicircular-arc shaped holing groove instead of the thread passinghole, thereby holding the upper thread 3 passing the space portion 15.

The take-out unit 25 is formed with the accommodating groove 29 toaccommodate the thread tension adjuster 21. Further, the take-out unit25 is rotated by the take-out driver 30 and partially winds the upperthread 3 on the thread contact portion 23 of the thread tension adjuster21.

In this embodiment, the take-out driver 30 includes the rotation shaft31 coupled to the take-out unit 25 and rotating, a driving shaft 33spaced from the rotation shaft 31 at a predetermined axis distance, ashaft driver to rotate the driving shaft 33, and a power transmissionunit to transmit a rotational force from the driving shaft 33 to therotation shaft 31.

The rotation shaft 31 is rotatably coupled to a frame 19 supported by ahead stem 17. The rotation shaft 31 has a first end coupled to thetake-out unit 25, and a second end coupled to a driven pulley 35.

The driving shaft 33 is parallel with the rotation shaft 31, androtatably coupled to the frame 19. The driving shaft 33 has a first endcoupled to a driving pulley 37 corresponding to the driven pulley 35.The driving pulley 37 and the driven pulley 35 are connected by a belt39 to transmit the rotational force from the driving shaft 33 to therotation shaft 31.

Further, the rotation shaft 31 and the driving shaft 33 are rotatablysupported by a bearing 41 accommodated and supported in the frame 19.

The driving shaft has a second end coupled to a driving cam 43 used asone element of the shaft driver to rotate the driving shaft 33. Further,a cam profile 43 a is formed on the outer circumference of the drivingcam 43 and curved along the lengthwise direction of the driving cam 43.The cam profile 43 a accommodates a driving pin 45 therein. The drivingpin 45 has a first end connected to a driving means (not shown), so thatthe driving cam 43 is rotated when the driving pin 45 is driven by thedriving means to move along the cam profile 43a of the driving cam 43.

Alternatively, the take-out driver 30 may be achieved by eitherconnecting a motor or a hydraulic cylinder as well as the foregoingstructure directly to the take-out unit 25, thereby rotating thetake-out unit 25. Further, in this embodiment, the driving pulley 37,the driven pulley 35, and belt 39 are employed as the power transmissionunit, but not limited to. Alternatively, a pair of gears engaged witheach other can be used in transmitting the rotation force of the drivingshaft 33 to the rotational shaft 31.

Further, the thread feeding apparatus 1 for the automatic embroideringmachine according to an embodiment of the present invention includes anoscillating bracket 71 oscillating to strengthen and release the tensionof the upper thread 3, a bracket driver 81 to drive the oscillatingbracket 71 to put the upper thread 3 on the oscillating bracket 71, andan oscillating bracket elastic member 91 for oscillating the oscillatingbracket 71 with predetermined elasticity.

The oscillating bracket 71 is coupled to a bush 75 rotatably fitted tothe outer circumference of the rotation shaft 31 of the take-out driver30. The oscillating bracket 71 has an upper end 71 a having asemicircular shape, a lower end 71 b spaced from the upper end 71 a at apredetermined distance and into which the bush 75 penetrates, and aconnecting portion 71 c connecting the upper end 71 a with one edge ofthe lower end 71 b and spacing the upper end 71 a from the lower end 71b. The upper end 71 a of the oscillating bracket 71 is provided with athread retainer 73 in which the upper thread 3 facing from the threadtension adjuster 21 toward the needle 13 is retained. In thisembodiment, a thread through hole is formed as the thread retainer 73.Alternatively, the upper end 71 a of the oscillating bracket 71 isformed with a semicircular-arc shaped holding groove instead of thethread through hole, thereby putting the upper thread 3 on the threadholding groove.

The bracket driver 81 moves the thread retainer 73 of the oscillatingbracket 71 to the thread transferring pat, thereby driving theoscillating bracket 71 to put the upper thread 3 on the thread retainer73. The bracket driver 81 includes a bracket driving cam 83 formed witha predetermined cam profile 83 a thereon, a moving pin 85 moving alongthe cam profile 83 a of the bracket driving cam 83, and a cam driver 87to move the moving pin 85 along the cam profile 83 a of the bracketdriving cam 83, thereby rotating the bracket driving cam 83.

The cam profile 83 a is formed on the outer circumference of the bracketdriving cam 83, inclined at a predetermined angle to the axis line ofthe bracket driving cam 83 along the lengthwise direction thereof, androtatably coupled to the bush 75.

The cam profile 83 a of the bracket driving cam 83 accommodates themoving pin 85 moving along the cam profile 83 a.

The moving pin 85 is connected to the cam driver 87 at one end thereof.Thus, when the cam driver 87 drives the moving pin 85 to move along thecam profile 83 a of the bracket driving cam 83, the bracket driving cam83 rotates. Here, a motor, a hydraulic cylinder, etc. can be used as thecam driver 87.

The oscillating bracket elastic member 91 is provided between theoscillating bracket 71 and the bracket driver 81. The oscillatingbracket elastic member 91 has a first end supported by the bracketdriving cam 83 and a second end supported by the oscillating bracket 71.Thus, the oscillating bracket 71 oscillates within a predeterminedsection by the oscillating bracket elastic member 91. In thisembodiment, a coil spring is used as the oscillating bracket elasticmember 91, but not limited to. Alternatively, a spiral spring or thelike as well as the coil spring can be used as the oscillating bracketelastic member 91.

Further, the bracket driver 81 can include a cam elastic member 95 toelastically rotate the bracket driving cam 83, thereby urging thebracket driving cam 83 to return to its original position. The camelastic member 95 has a first end supported by the bracket driving cam83, and a second end supported by the frame 19. In this embodiment, acoil spring is used as the cam elastic member 95, but not limited to.Alternatively, a spiral spring or the like as well as the coil springcan be used as the cam elastic member 95.

Therefore, when the upper thread 3 is replaced, the cam driver 87 drivesthe thread retainer 73 of the oscillating bracket 71 to move on thethread transferring path, and thus the moving pin 85 moves along the camprofile 83 a of the bracket driving cam 83. Then, the bracket drivingcam 83 rotates and allows the thread retainer 73 to communicate with theholder 27 of the take-out unit 25. At this time, the thread is nottangled in the oscillating bracket 71 even though the take-out unit 25rotates winding the upper thread 3 on the thread tension adjuster 21.

After retaining the upper thread 3 in the thread retainer 73 of theoscillating bracket 71, when the cam driver 87 drives the threadretainer 73 of the oscillating bracket 71 to be not aligned with theholder 27 of the take-out unit 25 and moves the moving pin 85 along thecam profile 83 a of the bracket driving cam 83, the oscillating bracket71 returns to its original position by the elasticity of the cam elasticmember 95. Thus, the upper thread 3 passing through the oscillatingbracket 71 is oscillated by the elasticity of the oscillating bracketelastic member 91 as well as the tension of the upper thread 3 adjustedby the thread tension adjuster 21, so that the tension of the upperthread 3 is strengthened and released.

Here, the oscillating bracket 71, the bracket driver 81, the oscillatingbracket elastic member 91 and the cam elastic member 95 can beoptionally provided.

With this configuration, when the upper thread 3 is replaced or cut as acolor is changed or the upper thread 3 is cut while embroidering, aprocess of adjusting the tension of the upper thread 3 supplied to theneedle 13 using the thread feeding apparatus 1 according to the firstembodiment of the present invention is as follows.

First, the take-out driver 30 is driven to place the holder 27 of thetake-out unit 25 on the thread transferring path of the space portion 15provided between the thread supplying unit 5 and the thread guide 8. Atthe same time, the oscillating bracket 71 is rotated to align the threadretainer 73 thereof with the holder 27 of the take-out unit 25. Aprocess of putting the upper thread 3 on the oscillating bracket 71 willbe described later.

Next, one upper thread 3 selected among the plurality of standby upperthreads different in color is supplied by the compressed air from thethread supplying unit 5 to the needle 13 via the thread supplyingchannel 6 of the thread supplying unit 5, the space portion 15, thethread guiding channel 9 of the thread guide 8.

As shown in FIGS. 5A and SB, the upper thread 3 come out of the threadsupplying channel 6 penetrates the thread retainer 73 of the oscillatingbracket 71 via the holder 27 of the take-out member 25, and is thenguided to the thread guiding channel 9 of the thread guide 8.

Then, the take-out unit 25 is rotated in one direction to partiallywinding the upper thread 3 on the thread contact portion 23 of thethread tension adjuster 21.

That is, the driving means (not shown) drives the driving pin 45 to movealong the cam profile 43 a of the driving cam 43, thereby rotating thedriving cam 43. As the driving cam 43 rotates, the driving shaft 33 isrotated and its rotational force is transmitted to the rotation shaft 31via the driving pulley 37 and the driven pulley 35 connected by the belt39, so that the take-out unit 25 rotates in one direction.

As the take-out unit 25 rotates, as shown in FIGS. 6A and 6B, the upperthread 3 held by the holder 27 of the take-out unit 25 is taken-out fromthe thread transferring path of the space portion 15, and then wound onthe thread contact portion 23 of the thread tension adjuster 21.Preferably, the take-out unit 25 is rotated once to wind the upperthread 3 on the thread contact portion 23 once.

Thus, the upper thread 3 wound on the thread contact portion 23 of thethread tension adjuster 21 is resisted while passing through the threadcontact portion 23 of the thread tension adjuster 21, therebystrengthening the tension of the upper thread 3 moving along the threadcontact portion 23.

After the upper thread 3 transferred to the thread guide 8 via thethread tension adjuster 21 is put on the thread retainer 73 of theoscillating bracket 71, the oscillating bracket 71 returns to itsoriginal position by the elasticity of the cam elastic member 95, andoscillates by the elasticity of the oscillating bracket elastic member91. Thus, the tension of the upper thread 3 passing through theoscillating bracket 71 is strengthened and released by not only itstension adjusted by the thread tension adjuster 21 but also theoscillation of the oscillating bracket 71.

Here, the process of putting the upper thread 3 on the thread retainer73 of the oscillating bracket 71 is as follows.

As shown in FIGS. 7A, the cam driver 87 drives the thread retainer 73 ofthe oscillating bracket 71 to be aligned with the holder 27 of thetake-out unit 25, and moves the moving pin 85 along the cam profile 83 aof the bracket driving cam 83. As shown in FIGS. 8A, 8B, 9A, 9B, 10A and10B, the bracket driving cam 83 rotates as the moving pin 85 movesupward along the cam profile 83 a of the bracket driving cam 83, so thatthe oscillating bracket 71 rotates. Therefore, the thread retainer 73 ofthe oscillating bracket 71 is aligned and communicates with the holder27 of the take-out unit 25 as shown in FIG. 7B.

Thus, one upper thread 3 selected among the plurality of standby upperthreads different in color is supplied by the compressed air from thethread supplying channel 6 of the thread supplying unit 5, retained inthe thread retainer 73 of the oscillating bracket 71 via the holder 27of the take-out unit 25, and transferred to the needle 13 via the threadguiding channel 9 of the thread guide 8.

Further, after retaining the upper thread 3 on the thread retainer 73 ofthe oscillating bracket 71, the cam driver 87 drives the thread retainer73 of the oscillating bracket 71 to be not aligned with the holder 27 ofthe take-out unit 25, and moves the moving pin 85 downward along the camprofile 83 a of the bracket driving cam 83. Then, as shown in FIG. 8A,the oscillating bracket 71 returns to its original position by theelasticity of the cam elastic member 95, and oscillates within apredetermined section, thereby strengthening and releasing the tensionof the upper thread 3.

Meanwhile, FIG. 11 is a partially enlarged perspective view of a threadfeeding apparatus for an automatic embroidering machine according to asecond embodiment of the present invention, and FIG. 12 is an explodedperspective view of FIG. 11. As shown therein, contrary to the firstembodiment, in a thread feeding apparatus 1′ for an automaticembroidering machine according to the second embodiment of the presentinvention, an oscillating bracket 71′ oscillating to strengthen andrelease the upper thread 3 is rotatably coupled to not the bush 75 ofthe take-out driver 30 but an auxiliary frame 51 coupled to the frame 19by a hinge pine 53 in a vertical direction. Here, the oscillatingbracket 71′ oscillates in the vertical direction corresponding to thethread take-up unit 11, i.e., between a top dead point and a bottom deadpoint.

The oscillating bracket 71′ according to the second embodiment of thepresent invention includes a pin coupling portion 71 a′ to which thehinge pin 53 is coupled, a tension plate 71 b′ bent and extended fromthe one side of the pin coupling portion 71 a′.

The tension plate 71 b′ of the oscillating bracket 71′ is provided witha thread retainer 73′ in which the upper thread 3 facing from the threadtension adjuster 21 toward the needle 13 is retained. In thisembodiment, a thread through hole is formed as the thread retainer 73′.Also, the thread retainer 73′ allows a thread take-out lever 7 topenetrate therethrough, wherein the thread take-out lever 7 is used asthe thread take-out unit for taking out the upper thread 3 transferredto the needle 13 via the thread supplying channel 6 and the threadguiding channel 9 when the upper thread 3 is replaced, and putting theupper thread 3 on the thread take-up unit 11. Here, the thread take-outlever 7 is installed at a predetermined angle to the thread guidingchannel 9 and reciprocates within a lever accommodating hole 10 formedin the thread guide 8.

Contrary to the first embodiment, a bracket driver 81′ according to thesecond embodiment of the present invention includes a tension plateclutch 88 nearing to and apart from the pin coupling portion 71 a′ ofthe oscillating bracket 71′, and a clutch driver 89 lifting up and downthe tension plate clutch 88.

In this embodiment, a hydraulic cylinder is employed as the clutchdriver 89 expanded and retracted by a hydraulic pressure andreciprocating the tension plate clutch 88. Alternatively, a motor, a camdevice, a solenoid, etc. can be used as the clutch driver 89 for drivingthe tension plate clutch 88.

Further, an oscillating bracket elastic member 91′ according to thesecond embodiment of the present invention has a first end supported bythe hinge pin 53, and a second end supported by the oscillating bracket71′. The oscillating bracket elastic member 91′ urges the oscillatingbracket 71′ to oscillate within a predetermined section, i.e., betweenthe top dead point and the bottom dead point. In this embodiment, atorsion spring is used as the oscillating bracket elastic member 91′.

In the meantime, an oscillating bracket control pin 97 is providedbetween the oscillating bracket 71′ and the tension plate clutch 88, andcoupled to an elongated hole 51 a of the auxiliary frame 51, so that itis used as a tension adjusting member for controlling the oscillation ofthe oscillating bracket 71′. Here, the oscillating bracket control pin97 is adjacent to the pin coupling portion 71 a′ of the oscillatingbracket 71′. As shown in FIGS. 14A and 14B, the oscillating bracketcontrol pin 97 is spaced from the pin coupling portion 71 a′ of theoscillating bracket 71′ when the tension of the upper thread 3 retainedin the thread retainer 73′ of the oscillating bracket 71′ isstrengthened, and is in contact with the pin coupling portion 71 a′ ofthe oscillating bracket 71′ when the tension of the upper thread 3retained in the thread retainer 73′ of the oscillating bracket 71′ isreleased. Further, the oscillating bracket control pin 97 is moved alongthe elongated hole S1 a of the auxiliary frame 51, thereby controllingthe bottom dead point of the oscillating bracket 71′, i.e., adjustingthe tension of the upper thread 3 transferred to the needle 13 via thethread take-up unit 11.

With this configuration, the tension of the upper thread 3 supplied tothe needle 13 using the thread feeding apparatus 1′ according to thesecond embodiment of the present invention is adjusted as follows.

According to the second embodiment, the process of winding the upperthread 3 on the thread contact portion 23 of the thread tension adjuster21 is the same as the foregoing process according to the firstembodiment, so that repetitive descriptions will be avoided asnecessary. Below, the process of adjusting the tension of the upperthread 3 retained in the thread retainer 73′ of the oscillating bracket71′ will be described.

In the state that the thread take-up unit is placed in the bottom deadpoint, the oscillating bracket 71′ is lift up and the clutch driver 89is driven, so that the thread retainer 73′ of the oscillating bracket71′ communicates with the lever accommodating hole 10 of the threadguide 8. Further, one upper thread 3 selected among the plurality ofstandby upper threads different in color is supplied by the compressedair from the thread supplying channel 6 of the thread supplying unit 5,retained in the thread retainer 73′ of the oscillating bracket 71′ viathe thread supplying channel 6 of the thread supplying unit 5 and theholder 27 of the take-out unit 25, and then transferred to the needle 13via the thread guiding channel 9 of the thread guide 8. At this time,the upper thread 3 transferring through the thread guiding channel 9 isheld by the thread take-out lever 7 accommodated in the leveraccommodating hole 10, and transferred to the needle 13.

Further, the thread take-out lever 7 is moved frontward to near thethread take-up unit 11, so that the thread take-out lever 7 passesthrough the thread retainer 73′ of the oscillating bracket 71′, therebyputting the upper thread 3 on the thread take-up unit 11.

After putting the upper thread 3 on the thread take-up unit 11, thethread take-out lever 7 is moved backward to be spaced from the threadtake-up unit 11, so that the thread take-out lever 7 comes out of thethread retainer 73′ of the oscillating bracket 71′ and is accommodatedin the lever accommodating hole 10 of the thread guide 8.

Further, after retaining the upper thread 3 in the thread retainer 73′of the oscillating bracket 71′, the clutch driver 89 is driven to makethe thread retainer 73′ of the oscillating bracket 71′ do notcommunicate with the lever accommodating hole 10 of the thread guide 8,thereby lifting down the oscillating bracket 71′. Then, the oscillatingbracket 71′ returns to its original position by the elasticity of theoscillating bracket elastic member 91′. That is, the thread retainer 73is placed at the top dead point of the oscillating bracket 71′.

Meanwhile, the upper thread 3 transferred to the needle 13 via thethread tension adjuster 21 and the thread guide 8 is held by the threadtake-out lever 7, and retained in the thread take-up unit 11 and thethread retainer 73 of the oscillating bracket 71′, and then the tensionof the upper thread 3 is strengthened and released by the oscillation ofthe thread take-up unit 11.

As shown in FIG. 13A and 14A, when the thread take-up unit 11 is placedat the top dead point, the tension plate 71 b′ of the oscillatingbracket 71′ is also placed at the top dead point, so the tension of theupper thread 3 is strengthened. On the other hand, as shown in FIG. 13Band 14B, when the thread take-up unit 11 is placed at the bottom deadpoint, the tension plate 71 b′ of the oscillating bracket 71′ is alsoplaced at the bottom dead point, so the tension of the upper thread 3 isreleased.

Therefore, the tension of the upper thread 3 passing through theoscillating bracket 71′ is strengthened and released by not only thetension of the upper thread 3 adjusted by the thread tension adjuster 21but also interaction of the oscillating bracket 71′ and the threadtake-up unit 11.

In particular, in the thread feeding apparatus 1′ according to thesecond embodiment of the present invention, the oscillating bracket 71′is more adjacent to the needle 13 than that of the first embodiment, sothat the tension of the upper thread 3 is more effectively adjusted.

Thus, when the take-out unit is rotated as holding the upper threadspaced from the axis line of the rotation shaft, the upper thread ispartially wound on the thread tension adjuster, and resisted whilepassing the thread tension adjuster, so that the tension of the upperthread is conveniently adjusted and work time is reduced.

In the meantime, it will be appreciated by those skilled in the art thatthe present invention is not limited to the single needle automaticembroidering machine and can be applied to a multi needle automaticembroidering machine.

As described above, the present invention provides a thread feedingapparatus for an automatic embroidering machine, which has an improvedstructure of adjusting the tension of an upper thread, thereby adjustingthe tension of the upper thread conveniently and reducing work time.

1. A thread feeding apparatus for an automatic embroidering machinesupplying an upper thread from a thread supplying unit to a needle,comprising: a thread tension adjuster having a thread contact portionallowing an upper thread to be at least partially wound thereon and bein contact therewith, and resisting the upper thread passing through thethread contact portion to adjust the tension of the upper thread; atake-out unit provided to rotate about a predetermined rotation axis,and rotated while holding the upper thread spaced from the rotation axisto put the upper thread on the thread tension adjuster; and a take-outdriver driving the thread take-out unit to rotate for at least partiallywinding the upper thread on the thread contact portion.
 2. The threadfeeding apparatus according to claim 1, wherein the take-out drivercomprises: a rotation shaft coupled to the take-out unit and rotating; adriving shaft spaced from the rotation shaft at a predetermined axisdistance; a shaft driver driving the driving shaft to rotate; and apower transmission unit provided between the rotation shaft and thedriving shaft and transmitting a rotational force from the driving shaftto the rotation shaft.
 3. The thread feeding apparatus according toclaim 1, further comprising: an oscillating bracket including a threadretainer to retain the upper thread transferred from the thread tensionadjuster to the needle, and oscillating to strengthen and release thetension of the upper thread; a bracket driver driving the oscillatingbracket to move the thread retainer of the oscillating bracket on athread transferring path and put the upper thread on the threadretainer; and an oscillating bracket elastic member elastically urgingthe oscillating bracket to oscillate.
 4. The thread feeding apparatusaccording to claim 1, wherein the bracket driver comprises: a bracketdriving cam formed with a cam profile on a lateral surface thereof; amoving pin moving along the camp profile of the bracket driving cam; anda cam driver to rotate the bracket driving cam by moving the moving pinalong the cam profile of the bracket driving cam, wherein theoscillating bracket elastic member has a first end supported by thebracket driving cam and a second end supported by the oscillatingbracket, and oscillates the oscillating bracket.
 5. The thread feedingapparatus according to claim 4, wherein the bracket driver furthercomprises a cam elastic member elastically rotating the bracket drivingcam to return an original position.
 6. The thread feeding apparatusaccording to claim 3, further comprising: a thread take-up unitoscillating within a predetermined section to strengthen and release thetension of the upper thread; and a thread-take-out unit taking out theupper thread transferred from the thread tension adjuster to the needleworking portion, and putting the upper thread on the thread take-up unitand the thread retainer, wherein the oscillating bracket oscillates in avertical direction corresponding to the thread take-up unit.
 7. Thethread feeding apparatus according to claim 6, wherein the threadretainer is placed at a top dead point of the oscillating bracket whenthe thread take-up unit is placed at a top dead point thereof, andplaced at a bottom dead point of the oscillating bracket when the threadtake-up unit is placed at a bottom dead point thereof.